Interpreting sharp loss of calc'd HP

[Bikey]

I am having a tough time reaching what I think my top speed should be and I noticed that calc'd HP is dropping like a brick. I have backed into the CdA based on my known dyno HP level, so I can compare different runs. I believe this drop shows that I have either an engine/tune issue (it is fine on the dyno) or an aero issue, but I just wanted to confirm there is nothing inherent in the Analysis power calculation that would result in this sharp drop off prior to reaching my top speed/letting off the gas.

[Bikey]

Well, I thought I had checked out prior data but this calc'd power dropoff seems to be inherent in the calculation as data from years past shows this behavior as well. It seems like the calculation averages a bit of data in front of and behind the given point for which the HP is calculated.

I assume the downward slope of the HP curve as speed rises is due to increasing drag from the aero bits, but let me know if anyone has other thoughts.

[Support]

there are a few seconds of filtering on the power figure as it can be very noisy...

Support (A)